1. Field of the Invention
This invention generally relates to reel units. More specifically, the present invention relates to reel units for spinning reels mounted to a fishing rod that winds fishing line onto its spool with a rotor that rotates in cooperation with rotation of a handle.
2. Background Information
Generally, spinning reels have a reel unit, a rotor rotatably supported by the reel unit, and a spool that is arranged in front of the rotor and on the outer periphery of which fishing line is wound by the rotor. The reel unit has a handle for rotating the rotor.
A reel unit generally has a casing and a mounting leg portion that are formed unitarily from an injection-molded synthetic resin or die-cast aluminum, and a cover portion. The casing accommodates a drive portion and has an opening for mounting the drive portion. The mounting leg portion has a leg portion extending upward from the casing and a fishing rod-mounting portion extending frontward and rearward from the tip of the leg portion. The cover portion is provided for covering the opening of the casing. The rotor is supported rotatably by the casing and is driven to rotate by a drive mechanism provided therein. The spool is supported by the casing so that it can shift back and forth, and an oscillating mechanism is provided therein to shift the spool back and forth. The rotation shaft of the handle is supported rotatably by the casing and the cover portion.
This type of spinning reel is required to be lightweight and be formed with a high degree of precision. As far as the casing is concerned, reduced weight and a high degree precision can be achieved when the wall thickness is reduced to reduce sink marks during the molding. However, the mounting leg portion needs to have a large wall thickness to maintain the relative strength. In the conventional configuration, however, the casing and the mounting leg portion are formed unitarily, and therefore, the casing is stretched by the thick-walled mounting leg portion during the molding. As a result, variation in thickness is caused in the thin-walled casing if the wall thickness of the casing is reduced to attain weight reduction and increased precision. For this reason, molding strain or non-uniform contraction is caused in the casing, which needs to be formed with a high degree of precision, and consequently, it is difficult to maintain a high degree of precision. If the wall thickness of the mounting leg portion is reduced in order to avoid this problem, the relative strength of the mounting leg portion is reduced and the mounting leg portion might be easily damaged. If the mounting leg portion is provided separately from the casing, the joint portion between the mounting leg portion and the casing needs to have large strength, necessitating a complex structure in the joint portion.
To address these issues, a reel unit for a spinning reel having a lid portion in which the cover portion and the mounting leg portion are formed unitarily is disclosed in Japanese Unexamined Patent Publication No. 10-004836. By providing the casing separately, it is possible to reduce the wall thickness of the casing and maintain a high degree of precision. Moreover, by forming the mounting leg portion unitarily with the cover portion, which does not need to be formed with so high a degree of precision, it is possible to increase the wall thickness of the mounting leg portion and to maintain the relative strength of the mounting leg portion.
In the conventional configuration, the lid portion formed unitarily with the mounting leg portion is made of metal, which has a high relative strength, to maintain a high degree of precision and relative strength. However, with a lid portion made of metal, if reduction in weight is desired while maintaining a high degree of precision and relative strength, it is necessary to use expensive metals such as titanium or the like, increasing the manufacturing cost.
In view of the above, there exists a need for reel unit for spinning reel which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.